The immune system plays a critical role in the pathogenesis of a wide variety of cancers. When cancers progress, it is widely believed that the immune system either fails to respond sufficiently or fails to respond appropriately, allowing cancer cells to grow. Currently, standard medical treatments for cancer, including chemotherapy, surgery, radiation therapy and cellular therapy, have clear limitations with regard to both efficacy and toxicity. To date, these approaches have met with varying degrees of success dependent upon the type of cancer, general health of the patient, stage of disease at the time of diagnosis, etc. Improved strategies that combine specific manipulation of the immune response to cancer in combination with standard medical treatments may provide a means for enhanced efficacy and decreased toxicity.
The use of autologous cancer cells as immunotherapies to augment anti-tumor immunity has been explored for some time (Oettgen et al., “The History of Cancer Immunotherapy”, In: Biologic Therapy of Cancer, Devita et al. (eds.) J. Lippincot Co., pp 87-199, 1991). However, due to the weak immunogenicity of many cancers, down regulation of MHC molecules, the lack of adequate costimulatory molecule expression and secretion of immunoinhibitory cytokines by cancer cells, the response to such immunotherapies has not resulted in long term efficacy. See, e.g., Armstrong T D and Jaffee E M, Surg Oncol Clin N Am. 11(3):681-96, 2002 and Bodey B et al, Anticancer Res 20(4):2665-76, 2000.
Numerous cytokines have been shown to play a role in regulation of the immune response to tumors. For example, U.S. Pat. No. 5,098,702 describes using combinations of TNF, IL-2 and IFN-beta in synergistically effective amounts to combat existing tumors. U.S. Pat. Nos. 5,078,996, 5,637,483 and 5,904,920 describe the use of GM-CSF for treatment of tumors. However, direct administration of cytokines for cancer therapy may not be practical, as they are often systemically toxic. (See, for example, Asher et al., J. Immunol. 146: 3227-3234, 1991 and Havell et al, J. Exp. Med. 167: 1067-1085, 1988.)
An expansion of this approach involves the use of genetically modified tumor cells which express cytokines locally at the immunotherapy site. Activity has been demonstrated in tumor models using a variety of immunomodulatory cytokines, including IL-4, IL-2, TNF-alpha, G-CSF, IL-7, IL-6 and GM-CSF, as described in Golumbeck P T et al., Science 254:13-716, 1991; Gansbacher B et al, J. Exp. Med. 172:1217-1224, 1990; Fearon E Ret al., Cell 60:397-403, 1990; Gansbacher B et al., Cancer Res. 50:7820-25, 1990; Teng M et al, PNAS 88:3535-3539, 1991; Columbo M P et al, J. Exp. Med. 174:1291-1298, 1991; Aoki et al., Proc Natl Acad Sci USA. 89(9):3850-4, 1992; Porgador A, et al., Nat Immun. 13(2-3):113-30, 1994; Dranoff G et al., PNAS 90:3539-3543, 1993; Lee C T et al, Human Gene Therapy 8:187-193, 1997; Nagai E et al, Cancer Immunol. Immonther. 47:2-80, 1998 and Chang A et al., Human Gene Therapy 11:839-850, 2000, respectively.
Clinical trials employing GM-CSF-expressing autologous or allogeneic cellular immunotherapies have commenced for treatment of prostate cancer, melanoma, lung cancer, pancreatic cancer, renal cancer, and multiple myeloma (Dummer R., Curr Opin Investig Drugs 2(6):844-8, 2001; Simons J et al, Cancer Res. 15; 59(20):5160-8, 1999; Soiffer R et al., PNAS 95:13141-13146, 1998; Simons J et al., Cancer Res. 15; 57:1537-1546, 1997; Jaffee E et al, J. Clin Oncol. 19:145-156, 2001; and Salgia R et al, J. Clin Oncol. 21:624-630, 2003).
In yet another approach, autologous tumor cells were genetically altered to produce a costimulatory molecule, such as B7-1 or allogeneic histocompatibility antigens (Salvadori et al. Hum. Gene Ther. 6:1299-1306, 1995 and Plaksin et al. Int. J. Cancer 59:796-801, 1994). While the use of genetically modified tumor cells has met with success in treatment of some forms of cancer, there remains a need for improved treatment regimens with greater potency and/or efficacy and fewer side effects than the therapies currently in use.